Electric switches



1956 R. c. SHARPLES ETAL 3,229,062

' ELECTRIC SWITCHES Filed March 1]., 1964 United States Patent 3,229,062 ELECTRIC SWITCHES Richard C. Sharples and Leslie J. Nevett, Burnley, England, assignors to Joseph Lucas (Industries) Limited, Birmingham, England Filed Mar. 11, 1964, Ser. No. 351,179 Claims priority, application Great Britain, Apr. 2, 1963, 12,951/ 63 1 Claim. (Cl. 200-67) The object of this invention is to provide an electric switch in a convenient and simple form.

A switch according to the invention comprises in combination a hollow body, an actuating member pivotally connected to the body, a contact member movable relative to the body between a first position in which it bridges a pair of contact pieces and a second position in which it is spaced from said contact pieces, and a resilient part pivotally engaged with the actuating member and the contact member, said part being formed from a synthetic resin and the arrangement being such that when the contact member is in its first or second position, angular movement of the actuating member will initially compress said part without moving the contact member, continued movement of the actuating member moving said part to a position in which it expands under its inherent resilience and moves the contact member to its second or first position, so that said part acts in the manner of an over-centre spring.

An example of the invention will be described with reference to the accompanying drawings in which:

FIGURE 1 is a front elevation view of a switch constructed in accordance with the present invention,

FIGURE 2 is a side elevation view in cross-section and,

FIGURE 3 is a cross sectional view on the line III-HI in FIGURE 2.

In the example shown in the drawings there is provided a hollow body which is formed from a synthetic resin such as that known as Delrin, to which is pivotally connected an actuating member 11. The actuating member includes a first arm extending from the body for manual operation, and a second and shorter arm extending into the body, and the actuating member is engaged in closed extremities of .two key hole shaped recesses 12 in the body so as to be freely rotatable, and assembly is by snapping axle portions 13 into the recesses 12.

The switch further includes a brass contact member 14 which comprises a pair of contact rollers 15 rigidly interconnected by an intermediate portion 16 of smaller crosssection, the axis of the contact member 14 being parallel to the pivot axis of the actuating member 11. The end of the body 10 remote from the actuating member 11 is closed by a cover 17 which is held in position by four projections 18 formed integrally on the inner walls of 'ice the body 10. The contact member 11 is movable between a first position in which it bridges a pair of metal contact pieces 19 secured in the body, and a second position in which it is spaced from the contact pieces. Extensions 20 of the contact pieces 19 extend from the body and are adapted for use as terminals. The contact member 14 is held against the cover 17 by a resilient part 21 acting between the actuating member 11 and contact member 14. This part 21 is also formed from Delrin or other resilient synthetic resin and is shaped to the form of an annulus. At diametrically opposite positions, the part 21 includes integral pairs of arms 22, 23 which engage respectively the second arm of the actuating member 11 and the intermediate portion 16 of the contact member 14, so that the part 21 is pivotally engaged with the actuating member and the contact member.

The resilient part 21 acts in effect as a combined toggle linkage and overcentre spring. Thus, when the contact member is in one or other of its positions, angular movement of the actuating member 11 initially compresses the part 21 without moving the contact member 14. After a predetermined movement, the actuating member reaches an angular position in which it is closest to the contact member and the compression of the part is at a maximum. Continued angular movement of the actuating member permits expansion of the part, and this expansion moves the contact member to its alternative position.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

A switch comprising a hollow body, an actuating member pivotally connected to the body, a contact member movable between first and second positions, a pair of contact pieces in the body and bridged by the contact member when in its first position, the contact member being spaced therefrom when in its second position, and a synthetic resinous resilient part of annular form engaging directly at one of its sides with the actuating member and engaging directly at its other side with the contact member, and when in either of the positions, the position of engagement between the resilient part and the actuating member is on one side of a plane containing the pivotal connection between the actuating member on the body, whereas the position of engagement between the resilient part and the contact member is on the opposite side of said plane.

References Cited by the Examiner UNITED STATES PATENTS 1,783,665 12/1930 Muer. 2,098,077 11/ 1937 White. 3,140,365 7/1964 Voland 200-159 X 3,165,603 1/1965 Sorenson 200 -68 X KATHLEEN CLAFFY, Primary Examiner. 

